Added OpenID Connect support (#307)

* Added OIDC support * Changed Dockerfile to multi-stage build * Reset Makefile to be usable with the new Dockerfile * Added page that will show the resulting login credentials * Disabled the go:generate command and the logging of the Version in line 209 since it always made some problems * Fixed a bug that the authentication server could not verify certificates of the OIDC provider * Fixed some bugs * Changed request of refreshing of the session by adding the ClientID and ClientSecret in the HTTP Basic authentication header. Furthermore added some comments. * Changed whole oidc_auth to use coreos/go-oidc package * fixed refreshAccessToken due to missing header * Fixes for Go 1.16 * Fixed Dockerfile * Fixed small thing in loggings * Added example in reference.yml * Delete .idea directory * adapt to go.mod of original repo * Update go.mod * undo stuff of before Co-authored-by: basels <frederik.basels@rwth-aachen.de> Co-authored-by: techknowlogick <techknowlogick@gitea.io>
cesanta · Oct 4, 2021 · cc91cb2 · cc91cb2
1 parent 9aa1b21
commit cc91cb2
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diff --git a/auth_server/authn/data/oidc_auth.tmpl b/auth_server/authn/data/oidc_auth.tmpl
@@ -0,0 +1,18 @@
+<!doctype html>
+
+<html>
+<head>
+  <meta charset="utf-8">
+  <title>Docker Registry Authentication</title>
+</head>
+
+<body>
+  <div id="panel">
+    <p>
+      <a id="login-with-oidc" href="{{.AuthEndpoint}}?response_type=code&scope=openid%20email&client_id={{.ClientId}}&redirect_uri={{.RedirectURI}}">
+        Login with OIDC Provider
+      </a>
+    </p>
+  </div>
+</body>
+</html>
diff --git a/auth_server/authn/data/oidc_auth_result.tmpl b/auth_server/authn/data/oidc_auth_result.tmpl
@@ -0,0 +1,17 @@
+<!doctype html>
+
+<html>
+<head>
+  <meta charset="utf-8">
+  <title>Docker Registry Authentication</title>
+</head>
+
+<body>
+  <p class="message">
+    You are successfully authenticated for the Docker Registry.
+    Use the following username and password to login into the registry:
+  </p>
+  <hr>
+  <pre class="command"><span>$ </span>docker login -u {{.Username}} -p {{.Password}} {{if .RegistryUrl}}{{.RegistryUrl}}{{else}}docker.example.com{{end}}</pre>
+</body>
+</html>
diff --git a/auth_server/authn/oidc_auth.go b/auth_server/authn/oidc_auth.go
@@ -0,0 +1,352 @@
+/*
+   Copyright 2015 Cesanta Software Ltd.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       https://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+*/
+
+package authn
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"golang.org/x/oauth2"
+	"html/template"
+	"io/ioutil"
+	"net/http"
+	"strings"
+	"time"
+
+	"github.com/coreos/go-oidc/v3/oidc"
+
+	"github.com/cesanta/glog"
+
+	"github.com/cesanta/docker_auth/auth_server/api"
+)
+
+// All configuration options
+type OIDCAuthConfig struct {
+	// --- necessary ---
+	// URL of the authentication provider. Must be able to serve the /.well-known/openid-configuration
+	Issuer string `yaml:"issuer,omitempty"`
+	// URL of the auth server. Has to end with /oidc_auth
+	RedirectURL string `yaml:"redirect_url,omitempty"`
+	// ID and secret, priovided by the OIDC provider after registration of the auth server
+	ClientId         string `yaml:"client_id,omitempty"`
+	ClientSecret     string `yaml:"client_secret,omitempty"`
+	ClientSecretFile string `yaml:"client_secret_file,omitempty"`
+	// path where the tokendb should be stored within the container
+	TokenDB string `yaml:"token_db,omitempty"`
+	// --- optional ---
+	HTTPTimeout int `yaml:"http_timeout,omitempty"`
+	// the URL of the docker registry. Used to generate a full docker login command after authentication
+	RegistryURL string `yaml:"registry_url,omitempty"`
+}
+
+// OIDCRefreshTokenResponse is sent by OIDC provider in response to the grant_type=refresh_token request.
+type OIDCRefreshTokenResponse struct {
+	AccessToken  string `json:"access_token,omitempty"`
+	ExpiresIn    int64  `json:"expires_in,omitempty"`
+	TokenType    string `json:"token_type,omitempty"`
+	RefreshToken string `json:"refresh_token,omitempty"`
+
+	// Returned in case of error.
+	Error            string `json:"error,omitempty"`
+	ErrorDescription string `json:"error_description,omitempty"`
+}
+
+// ProfileResponse is sent by the /userinfo endpoint or contained in the ID token.
+// We use it to validate access token and (re)verify the email address associated with it.
+type OIDCProfileResponse struct {
+	Email         string `json:"email,omitempty"`
+	VerifiedEmail bool   `json:"verified_email,omitempty"`
+	// There are more fields, but we only need email.
+}
+
+// The specific OIDC authenticator
+type OIDCAuth struct {
+	config     *OIDCAuthConfig
+	db         TokenDB
+	client     *http.Client
+	tmpl       *template.Template
+	tmplResult *template.Template
+	ctx        context.Context
+	provider   *oidc.Provider
+	verifier   *oidc.IDTokenVerifier
+	oauth      oauth2.Config
+}
+
+/*
+Creates everything necessary for OIDC auth.
+*/
+func NewOIDCAuth(c *OIDCAuthConfig) (*OIDCAuth, error) {
+	db, err := NewTokenDB(c.TokenDB)
+	if err != nil {
+		return nil, err
+	}
+	glog.Infof("OIDC auth token DB at %s", c.TokenDB)
+	ctx := context.Background()
+	oidcAuth, _ := static.ReadFile("data/oidc_auth.tmpl")
+	oidcAuthResult, _ := static.ReadFile("data/oidc_auth_result.tmpl")
+
+	prov, err := oidc.NewProvider(ctx, c.Issuer)
+	if err != nil {
+		return nil, err
+	}
+	conf := oauth2.Config{
+		ClientID:     c.ClientId,
+		ClientSecret: c.ClientSecret,
+		Endpoint:     prov.Endpoint(),
+		RedirectURL:  c.RedirectURL,
+		Scopes:       []string{oidc.ScopeOpenID, "email"},
+	}
+	return &OIDCAuth{
+		config:     c,
+		db:         db,
+		client:     &http.Client{Timeout: 10 * time.Second},
+		tmpl:       template.Must(template.New("oidc_auth").Parse(string(oidcAuth))),
+		tmplResult: template.Must(template.New("oidc_auth_result").Parse(string(oidcAuthResult))),
+		ctx:        ctx,
+		provider:   prov,
+		verifier:   prov.Verifier(&oidc.Config{ClientID: conf.ClientID}),
+		oauth:      conf,
+	}, nil
+}
+
+/*
+This function will be used by the server if the OIDC auth method is selected. It starts the page for OIDC login or
+requests an access token by using the code given by the OIDC provider.
+*/
+func (ga *OIDCAuth) DoOIDCAuth(rw http.ResponseWriter, req *http.Request) {
+	code := req.URL.Query().Get("code")
+	if code != "" {
+		ga.doOIDCAuthCreateToken(rw, code)
+	} else if req.Method == "GET" {
+		ga.doOIDCAuthPage(rw)
+	} else {
+		http.Error(rw, "Invalid auth request", http.StatusBadRequest)
+	}
+}
+
+/*
+Executes tmpl for the OIDC login page.
+*/
+func (ga *OIDCAuth) doOIDCAuthPage(rw http.ResponseWriter) {
+	if err := ga.tmpl.Execute(rw, struct {
+		AuthEndpoint, RedirectURI, ClientId string
+	}{
+		AuthEndpoint: ga.provider.Endpoint().AuthURL,
+		RedirectURI:  ga.oauth.RedirectURL,
+		ClientId:     ga.oauth.ClientID,
+	}); err != nil {
+		http.Error(rw, fmt.Sprintf("Template error: %s", err), http.StatusInternalServerError)
+	}
+}
+
+/*
+Executes tmplResult for the result of the login process.
+*/
+func (ga *OIDCAuth) doOIDCAuthResultPage(rw http.ResponseWriter, un string, pw string) {
+	if err := ga.tmplResult.Execute(rw, struct {
+		Username, Password, RegistryUrl string
+	}{
+		Username:    un,
+		Password:    pw,
+		RegistryUrl: ga.config.RegistryURL,
+	}); err != nil {
+		http.Error(rw, fmt.Sprintf("Template error: %s", err), http.StatusInternalServerError)
+	}
+}
+
+/*
+Requests an OIDC token by using the code that was provided by the OIDC provider. If it was successfull,
+the access token and refresh token is used to create a new token for the users mail address, which is taken from the ID
+token.
+*/
+func (ga *OIDCAuth) doOIDCAuthCreateToken(rw http.ResponseWriter, code string) {
+
+	tok, err := ga.oauth.Exchange(ga.ctx, code)
+	if err != nil {
+		http.Error(rw, fmt.Sprintf("Error talking to OIDC auth backend: %s", err), http.StatusInternalServerError)
+		return
+	}
+	rawIdTok, ok := tok.Extra("id_token").(string)
+	if !ok {
+		http.Error(rw, "No id_token field in oauth2 token.", http.StatusInternalServerError)
+		return
+	}
+	idTok, err := ga.verifier.Verify(ga.ctx, rawIdTok)
+	if err != nil {
+		http.Error(rw, fmt.Sprintf("Failed to verify ID token: %s", err), http.StatusInternalServerError)
+		return
+	}
+	var prof OIDCProfileResponse
+	if err := idTok.Claims(&prof); err != nil {
+		http.Error(rw, fmt.Sprintf("Failed to get mail information from ID token: %s", err), http.StatusInternalServerError)
+		return
+	}
+	if prof.Email == "" {
+		http.Error(rw, fmt.Sprintf("No mail information given in ID token"), http.StatusInternalServerError)
+		return
+	}
+
+	glog.V(2).Infof("New OIDC auth token for %s (Current time: %s, expiration time: %s)", prof.Email, time.Now().String(), tok.Expiry.String())
+
+	dbVal := &TokenDBValue{
+		TokenType:    tok.TokenType,
+		AccessToken:  tok.AccessToken,
+		RefreshToken: tok.RefreshToken,
+		ValidUntil:   tok.Expiry.Add(time.Duration(-30) * time.Second),
+	}
+	dp, err := ga.db.StoreToken(prof.Email, dbVal, true)
+	if err != nil {
+		glog.Errorf("Failed to record server token: %s", err)
+		http.Error(rw, "Failed to record server token: %s", http.StatusInternalServerError)
+		return
+	}
+
+	ga.doOIDCAuthResultPage(rw, prof.Email, dp)
+}
+
+/*
+Refreshes the access token of the user. Not usable with all OIDC provider, since not all provide refresh tokens.
+*/
+func (ga *OIDCAuth) refreshAccessToken(refreshToken string) (rtr OIDCRefreshTokenResponse, err error) {
+
+	url := ga.provider.Endpoint().TokenURL
+	pl := strings.NewReader(fmt.Sprintf(
+		"grant_type=refresh_token&client_id=%s&client_secret=%s&refresh_token=%s",
+		ga.oauth.ClientID, ga.oauth.ClientSecret, refreshToken))
+	req, err := http.NewRequest("POST", url, pl)
+	if err != nil {
+		err = fmt.Errorf("could not create refresh request: %s", err)
+		return
+	}
+	req.Header.Add("content-type", "application/x-www-form-urlencoded")
+
+	resp, err := ga.client.Do(req)
+	if err != nil {
+		err = fmt.Errorf("error talking to OIDC auth backend: %s", err)
+		return
+	}
+	respStr, _ := ioutil.ReadAll(resp.Body)
+	glog.V(2).Infof("Refresh token resp: %s", strings.Replace(string(respStr), "\n", " ", -1))
+
+	err = json.Unmarshal(respStr, &rtr)
+	if err != nil {
+		err = fmt.Errorf("error in reading response of refresh request: %s", err)
+		return
+	}
+	if rtr.Error != "" || rtr.ErrorDescription != "" {
+		err = fmt.Errorf("%s: %s", rtr.Error, rtr.ErrorDescription)
+		return
+	}
+	return rtr, err
+}
+
+/*
+In case the DB token is expired, this function uses the refresh token and tries to refresh the access token stored in the
+DB. Afterwards, checks if the access token really authenticates the user trying to log in.
+*/
+func (ga *OIDCAuth) validateServerToken(user string) (*TokenDBValue, error) {
+	v, err := ga.db.GetValue(user)
+	if err != nil || v == nil {
+		if err == nil {
+			err = errors.New("no db value, please sign out and sign in again")
+		}
+		return nil, err
+	}
+	if v.RefreshToken == "" {
+		return nil, errors.New("refresh of your session is not possible. Please sign out and sign in again")
+	}
+
+	glog.V(2).Infof("Refreshing token for %s", user)
+	rtr, err := ga.refreshAccessToken(v.RefreshToken)
+	if err != nil {
+		glog.Warningf("Failed to refresh token for %q: %s", user, err)
+		return nil, fmt.Errorf("failed to refresh token: %s", err)
+	}
+	v.AccessToken = rtr.AccessToken
+	v.ValidUntil = time.Now().Add(time.Duration(rtr.ExpiresIn-30) * time.Second)
+	glog.Infof("Refreshed auth token for %s (exp %d)", user, rtr.ExpiresIn)
+	_, err = ga.db.StoreToken(user, v, false)
+	if err != nil {
+		glog.Errorf("Failed to record refreshed token: %s", err)
+		return nil, fmt.Errorf("failed to record refreshed token: %s", err)
+	}
+	tokUser, err := ga.provider.UserInfo(ga.ctx, oauth2.StaticTokenSource(&oauth2.Token{AccessToken: v.AccessToken,
+		TokenType:    v.TokenType,
+		RefreshToken: v.RefreshToken,
+		Expiry:       v.ValidUntil,
+	}))
+	if err != nil {
+		glog.Warningf("Token for %q failed validation: %s", user, err)
+		return nil, fmt.Errorf("server token invalid: %s", err)
+	}
+	if tokUser.Email != user {
+		glog.Errorf("token for wrong user: expected %s, found %s", user, tokUser.Email)
+		return nil, fmt.Errorf("found token for wrong user")
+	}
+	texp := v.ValidUntil.Sub(time.Now())
+	glog.V(1).Infof("Validated OIDC auth token for %s (exp %d)", user, int(texp.Seconds()))
+	return v, nil
+}
+
+/*
+First checks if OIDC token is valid. Then delete the corresponding DB token from the database. The user is now signed out
+Not deleted because maybe it will be implemented in the future.
+*/
+//func (ga *OIDCAuth) doOIDCAuthSignOut(rw http.ResponseWriter, token string) {
+//	// Authenticate web user.
+//	ui, err := ga.validateIDToken(token)
+//	if err != nil || ui == ""{
+//		http.Error(rw, fmt.Sprintf("Could not verify user token: %s", err), http.StatusBadRequest)
+//		return
+//	}
+//	err = ga.db.DeleteToken(ui)
+//	if err != nil {
+//		glog.Error(err)
+//	}
+//	fmt.Fprint(rw, "signed out")
+//}
+
+/*
+Called by server. Authenticates user with credentials that were given in the docker login command. If the token in the
+DB is expired, the OIDC access token is validated and, if possible, refreshed.
+*/
+func (ga *OIDCAuth) Authenticate(user string, password api.PasswordString) (bool, api.Labels, error) {
+	err := ga.db.ValidateToken(user, password)
+	if err == ExpiredToken {
+		_, err = ga.validateServerToken(user)
+		if err != nil {
+			return false, nil, err
+		}
+	} else if err != nil {
+		return false, nil, err
+	}
+	return true, nil, nil
+}
+
+func (ga *OIDCAuth) Stop() {
+	err := ga.db.Close()
+	if err != nil {
+		glog.Info("Problems at closing the token DB")
+	} else {
+		glog.Info("Token DB closed")
+	}
+}
+
+func (ga *OIDCAuth) Name() string {
+	return "OpenID Connect"
+}